Electrophotographic printing system

Abstract

Reproductions of originals are obtained electro-photographically by exposing a charged photoconductor sequentially to at least two electro-optically regulated laser beam exposures, each exposure representing a separate color component of the original. Full color reproduction is possible. Alternatively a laser beam exposure may be accompanied, preferably substantially simultaneously, by exposures from either an opaque original or a transparency or both.

What is claimed is: 
     
       1. Electrophotographic composite printing apparatus comprising a recyclable photoconductive member and charging means for uniformly, electrostatically charging the surface of the photoconductive member each cycle of the member in preparation for creation of a latent electrostatic image each cycle subsequent to the uniform charging of the surface of the photoconductive member,   composite exposure means for exposing to electromagnetic radiation the charged surface of the photoconductive member for creation of latent electrostatic images thereon, the composite exposure means including optical projection means for exposing a first selected region of the uniformly charged surface during a cycle of the photoconductive member to an electromagnetic radiation image of an original projected onto the first selected region by means including a projection lens for creating a first latent electrostatic image and laser exposure means for exposing a second nonoverlapping region of the charged surface, during the same cycle of the photoconductive member that the first region is exposed, to a data controlled raster scan image created by a moving spot of electromagnetic radiation generated by a laser for creating a second latent electrostatic image which with the first latent image comprises a composite latent electrostatic image,   development means for substantially simultaneously developing with toner material the first and second latent electrostatic images during the same cycle of the photoconductive member that the first and second charged regions are exposed for creating a visible composite toner image corresponding to the composite latent image and   transfer means for transferring the composite toner image to a support member during the cycle of the photoconductive member in which the toner image is created.   
     
     
       2. The apparatus of claim 1 wherein the laser and projection exposure means are aligned relative to the photoconductive member for substantially simultaneous exposure of the first and second regions of the charged surface of the photoconductive member for creation of the composite latent image. 
     
     
       3. The apparatus of claim 1 wherein said photoconductive member is a drum mounted for rotation and wherein the transfer means includes registration transfer means for transferring a first composite toner image to a support member during one cycle and for transferring a second and subsequent composite toner images made respectively during second and subsequent cycles to the same support member in registration with the first composite toner image. 
     
     
       4. The apparatus of claim 3 wherein said development means includes magenta toner developer means for developing a first composite latent image generated during a first cycle of the photoconductive member with magenta toner material,   yellow developer means for developing a second composite latent image generated during a second cycle of the photoconductive member with yellow toner material and   cyan developer means for developing a third composite latent image generated during a third cycle of the photoconductive member with cyan toner material   whereby a full color composite image is obtained following transfer to a support member of magenta, yellow and cyan toner images.   
     
     
       5. The apparatus of claim 1 wherein the projection exposure means includes means for projecting images of opaque originals to the photoconductive member. 
     
     
       6. The apparatus of claim 1 wherein the projection exposure means includes means for projecting images of transparency originals to the photoconductive member. 
     
     
       7. The apparatus of claim 1 wherein said projection exposure means includes means for projecting simultaneously non-overlapping images of an opaque and transparency originals. 
     
     
       8. The apparatus of claim 1 wherein said laser exposure means includes a galvanometer optical scanner and an accousto-optical modulator wherein the scanner sweeps a laser beam over the second selected region of the charged surface and the modulator selectively varies the instantaneous intensity of the laser beam.